Studies on the scale-up of crossflow filtration devices.

This paper describes a new method that makes it possible to predict the performance of crossflow ultrafiltration and microfiltration when scaling up from small laboratory scale to process-scale systems. Using this method, one characterizes a solution's filtration properties with a specific ultrafiltration or microfiltration membrane in a laboratory-scale crossflow device. Based on experimental results at this scale, one can accurately predict scale-up performance from laboratory through clinical production to full marketing production. Given the need for biopharmaceutical engineers to rapidly predict the size and cost of full-scale filtration processes once products receive regulatory approval, this method will find wide use in the pharmaceutical industry.

Studies on the scale-up of microfiltration membrane devices.

This paper addresses the prediction and modeling of fouling in microfiltration (MF) membrane devices during the filtration of biological solutions. The membrane-fouling model described can be used by bioengineers to characterize a solution's filterability when using a specific microfiltration product line. This allows bioengineers to predict the scale up of filtration from laboratory through clinical production to full marketing production. The model used to correlate filtration results contains two parameters (initial flux and membrane plugging constant) that must be determined experimentally. Once these parameters are known, it is possible to predict the performance (fouling and throughput) of larger membrane devices as a function of operating pressure, processing time, and membrane area. This allows users of MF devices to perform laboratory tests of their solution at relatively small scale, and based on these tests determine the performance of larger-scale MF devices for filtration of the same solution.

A membrane-based method for removal of toxic ammonia from mammalian-cell culture.

Many mammalian cells grown in culture excrete ammonia, which, when it accumulates, limits cell growth and reduces product synthesis. Common tactics for minimizing the effects of ammonia accumulation are uneconomical, requiring large quantities of media and incurring high capital costs. Solution-diffusion membranes were investigated for ammonia removal, and a supported-gas membrane was identified that could be used to remove ammonia rapidly to well below inhibitory levels. Medium treated using this membrane was reused to culture baby-hamster kidney cells, resulting in a cell growth rate that was essentially the same as that for cells grown in fresh medium.

[Clinical and construction of combined fixed and removable prostheses in the lacunar set of teeth]. / Klinik und Konstruktion kombinierter festsitzender und abnehmbarer Prothesen im Lückengebiss.

Decisive for a long-term maintenance of the structure of the oral tissues for the prosthetic providing by combined fixed and removable prosthesises are the preparation of the residual set of teeth according to the therapy, the periodontally supported coupling by suitable connecting elements, and the scaffold construction corresponding to a suitable saddlekinematies. The basis for all that are a rather fixed connection with the residual set of teeth and simultaneously the consideration of perioprosthetic constructive principles. The coupling may be done by casting cramps, telescopes or debris, having a different valency.

[Receptor functions of the mouth mucosa and their influence by prosthetic therapy]. / Die Rezeptorfunktionen der Mundschleimhaut und ihre Beeinflussung durch prothetische Therapiemittel.

The oralstereognostic and muscular-motoric ability of patients wearing different removable partial dentures was examined with the aid of different testbodies. As shown by the results the lingual-dental shill of patients was improved by dentures and denture adaptation was mainly dependent on the age of the person and not on extrusion.